package com.k.util;

public class StringUtils {
    // true: null, "", "   "
    public static boolean isBlank(CharSequence cs) {
        int strLen = cs == null ? 0 : cs.length();
        if (strLen != 0) {
            for (int i = 0; i < strLen; ++i) {
                if (!Character.isWhitespace(cs.charAt(i))) {
                    return false;
                }
            }
        }
        return true;
    }

    public static boolean isNotBlank(CharSequence cs) {
        return !isBlank(cs);
    }

    // true: null, ""
    public static boolean isEmpty(CharSequence cs) {
        return cs == null || cs.length() == 0;
    }

    public static boolean isNotEmpty(CharSequence cs) {
        return !isEmpty(cs);
    }
}
